KR20240039615A - Secondary battery, manufacturing method thereof, battery module, battery pack, and electrical device - Google Patents

Abstract

The present invention provides a secondary battery, wherein the secondary battery includes a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte, and at least one of the negative electrode material layer, the positive electrode material layer, and the electrolyte includes an interface passivator, , the interface passivator is a compound containing the element E, wherein E is selected from lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, gallium or germanium. The present invention also relates to a method of manufacturing a secondary battery, a battery module including the secondary battery, a battery pack, and an electrical device. The secondary battery of the present invention has improved impedance and balanced cycle performance and storage performance.

Description

Secondary battery, manufacturing method thereof, battery module, battery pack, and electrical device

The present invention relates to the field of lithium battery technology, and particularly to secondary batteries, methods for manufacturing the same, battery modules containing the secondary batteries, battery packs, and electrical devices.

With the widespread application of electric vehicles (EV) and hybrid electric vehicles (HEV), people are paying more attention to the vehicle usage time and usage costs. Therefore, the cycle life of secondary batteries, which are energy storage devices for vehicles, has naturally become one of the performance focuses of attention in the field. As expected, secondary batteries have excellent cycle performance and long battery life. This not only reduces user usage costs, but also means less resource consumption.

Conventional technology cannot effectively improve the cycle performance of secondary batteries, and it is difficult to balance cycle performance and storage performance. Accordingly, secondary batteries with improved cycle and storage performance and methods for manufacturing the same are required in the art.

The present invention was developed in consideration of the above problems, and its purpose is to provide a secondary battery with improved cycle and storage performance and a method for manufacturing the same.

To achieve the above object, the present invention provides a secondary battery, a manufacturing method thereof, a battery module, a battery pack, and an electrical device.

A first aspect of the present invention provides a secondary battery, wherein the secondary battery includes a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or germanium. By including an interfacial passivator, the secondary battery can create a beneficial ternary layer on the surface of the negative electrode material layer.

In certain embodiments, the surface of the cathode material layer has an A-D-E ternary layer, wherein A is selected from an alkali metal element and is different from E, and D is silicon or carbon; The A-D-E ternary layer is formed when the interface passivator acts on the surface of the negative electrode material layer during at least one charging process of the secondary battery. Since the secondary battery of the present invention is provided with a ternary passivation layer on the surface of the negative electrode material layer, battery impedance can be significantly reduced and battery cycle life and storage performance can be improved.

In certain embodiments, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum, and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum. By selecting a compound containing the metal element, the stabilization effect of the ternary layer can be further improved, thereby more effectively improving the performance of the secondary battery.

In certain embodiments, the interfacial passivator is selected from at least one of substituted or unsubstituted C _1-20 carboxylates, and the substituents are C _1-6 alkyl, C _2-6 cycloalkyl, hydroxyl, amino , oxo group, acyl, C _1-6 alkylthio, phenyl, benzoylthio, phenylthio and phenoxy; iminoates; enoates; phosphate; sulfate; sulfonimide salt; sulfonate; benzoate; phthalate; acetylacetonate; inorganic oxoates; and at least one selected from double salts containing two or more of the above non-transition metal cations. By selecting the above compound as an interface passivator, the resistance, cycle life, and storage performance of the secondary battery can be more effectively improved.

In certain embodiments, the interfacial passivator is blended into at least one of the anode material layer, the cathode material layer, and the electrolyte solution. By adding an interfacial passivator to the positive electrode material, negative electrode material, and electrolyte solution by blending, the performance of the secondary battery can be effectively improved.

In certain embodiments, the A-D-E ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Li-C-Ca, Li-C-Mg, Li- C-Be, Li-C-Al, Na-Si-Ca, Na-Si-Mg, Na-Si-Be, Na-Si-Al, Na-C-Ca, Na-C-Mg, Na-C- selected from Be, Na-C-Al ternary hierarchy, and combinations thereof; Optionally, the A-D-E ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Na-Si-Ca, Na-Si-Mg, Na-Si-Be, It is selected from Na-Si-Al ternary layers and combinations thereof. By including the above three-layer layer in a secondary battery, battery impedance, cycle life, and storage performance can be effectively improved.

In certain embodiments, before the at least one charge, the positive electrode material layer includes 0.001% to 20% by weight, optionally 1% to 10% by weight of the interface pass, based on the total weight of the positive electrode material layer. Including baiters.

In certain embodiments, before the at least one charge, the cathode material layer contains 0.001 wt% to 20 wt%, optionally 0.05 wt% to 5 wt% of the interface pass, based on the total weight of the cathode material layer. Including baiters.

In certain embodiments, before the at least one charge, the electrolyte contains 0.001% to 20% by weight, optionally 0.1% to 5% by weight of the interfacial passivator, based on the total weight of the electrolyte. Includes.

By controlling the passivator content within the above range, battery performance can be further improved.

In certain embodiments, the negative electrode material layer includes a negative electrode active material, and the D50 of the negative electrode active material is 1 μm to 20 μm, optionally 2 μm to 10 μm. By applying the negative electrode active material having the above D50, the function of the ternary interface passivation layer of the present invention can be effectively exerted, thereby significantly improving the performance of the secondary battery.

In certain embodiments, the negative electrode material layer includes a negative electrode active material, and the negative electrode active material has a Span value of 0.9 to 1.8, optionally 0.9 to 1.2;

and

D90, D10 and D50 represent the corresponding particle sizes when the cumulative distribution percentage is 90%, 10% and 50%, respectively. By selecting a negative electrode active material with a Span value within the above range, it is advantageous for the material to have relative interfacial stability and is helpful in implementing the effect of improving battery performance.

A second aspect of the present invention provides a secondary battery, the secondary battery comprising:

i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and

ii) It is manufactured through the step of performing at least one charge/discharge cycle on a secondary battery that has not gone through the above cycle.

A third aspect of the present invention provides a method for manufacturing a secondary battery, the method comprising:

i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and

ii) performing at least one charge/discharge cycle on the secondary battery that has not gone through the cycle to form an A-D-E ternary layer to obtain the secondary battery; A is selected from an alkali metal element and is different from E, and D is silicon or carbon.

Through the above method, a secondary battery having a ternary passivation layer on the surface of the negative electrode material layer can be obtained, improving the impedance, cycle life, and storage performance of the secondary battery.

In certain embodiments, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum, and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum. By selecting the interface passivator to effectively form a ternary layer, performance, such as cycle and storage, of the secondary battery can be improved.

In certain embodiments, the interfacial passivator is selected from at least one of substituted or unsubstituted C _1-20 carboxylates, and the substituents are C _1-6 alkyl, C _2-6 cycloalkyl, hydroxyl, amino , oxo group, acyl, C _1-6 alkylthio, phenyl, benzoylthio, phenylthio and phenoxy; iminoates; enoates; phosphate; sulfate; sulfonimide salt; sulfonate; benzoate; phthalate; acetylacetonate; inorganic oxoates; and at least one selected from double salts containing two or more of the above non-transition metal cations. By selecting the interface passivator, a secondary battery with significantly improved resistance, cycle life, and storage performance can be manufactured.

In certain embodiments, in step i), the interfacial passivator is blended into at least one of the anode material layer, the cathode material layer, and the electrolyte solution. Blending makes it easier to form a ternary layer, which can further improve the performance of secondary batteries.

A fourth aspect of the present invention provides a battery module including the secondary battery of the first and second aspects of the present invention or the secondary battery obtained by the method of the third aspect of the present invention.

A fifth aspect of the present invention provides a battery pack including the battery module of the fourth aspect of the present invention.

The sixth aspect of the present invention includes at least one of the secondary batteries of the first and second aspects of the present invention, the secondary battery obtained by the method of the third aspect, the battery module of the fourth aspect, or the battery pack of the fifth aspect of the present invention. Provides electrical equipment.

The secondary battery of the present invention and the secondary battery obtained by the manufacturing method of the present invention have balanced cycle performance and storage performance and have low internal resistance.

1 is a schematic diagram of a secondary battery according to an embodiment of the present invention.
FIG. 2 is an exploded view of a secondary battery according to an embodiment of the present invention shown in FIG. 1.
Figure 3 is a schematic diagram of a battery module according to an embodiment of the present invention.
Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present invention.
Figure 5 is an exploded view of the battery pack according to an embodiment of the present invention shown in Figure 4.
Figure 6 is a schematic diagram of an electric device using a secondary battery as a power source according to an embodiment of the present invention.

Hereinafter, embodiments of the negative electrode plate, secondary battery, battery module, battery pack, and electric device of the present invention will be described in detail and disclosed in detail with appropriate reference to the accompanying drawings. However, in some cases, unnecessary detailed descriptions are omitted. For example, detailed descriptions of notices and repetitive descriptions of structures that are actually the same may be omitted. This is to prevent unnecessary repetition of the following description and to make it easier for those skilled in the art to understand. In addition, the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present invention, and are not intended to limit the subject matter described in the claims.

A "range" disclosed herein is defined in the form of a lower limit and an upper limit, where a given range is defined by the selection of one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. In this way, Defined ranges may or may not include endpoint values and can be arbitrarily combined, i.e. any lower limit and any upper limit can be combined to form a range, for example 60~120 and 80~ If a range of 110 is listed for a particular parameter, it should be understood that the ranges of 60 to 110 and 80 to 120 are also considered. Additionally, minimum range values 1 and 2 are listed and maximum range values 3, 4, and 5 are listed. All ranges 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5 are expected. In the present invention, unless otherwise specified, the numerical range "a to b" is a Represents an abbreviated representation of a combination of real numbers between and b, where a and b are both real numbers. For example, the numeric range "0 to 5" means that all real numbers between "0 and 5" are listed herein. And "0~5" is only an abbreviated expression of a combination of these numerical values. Additionally, when a specific parameter is expressed as an integer with ≥2, the parameter in question is, for example, 2, 3, 4, 5, 6. , 7, 8, 9, 10, 11, 12, etc. are the same as disclosing that they are integers.

Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

Unless otherwise specified, all steps of the present invention can be performed sequentially or randomly, and are preferably performed sequentially. For example, the method may include steps (a) and (b), which may include steps (a) and (b) performed sequentially, and which may include steps (b) and ( Indicates that a) may be included. For example, the method mentioned may further comprise step (c), indicating that step (c) can be added to the method in any order, for example, the method may include step ( may include steps (a), (b) and (c), may include steps (a), (c) and (b), may include steps (c), (a) and (b), etc. It may be possible.

Unless otherwise specified, “inclusive” and “including” mentioned in the present invention may mean open and closed forms. For example, the above “comprehensive” and “includes” indicate that it may further encompass or include other ingredients that are not listed, and that it encompasses or includes only the listed ingredients.

Unless otherwise specified, the term “or” in the present disclosure is inclusive. For example, the phrase “A or B” refers to “A, B, or both A and B.” More specifically, A is true (or present) and B is false (or absent); A is false (or absent) and B is true (or present); Or, one of the conditions in which both A and B are true (or exists) satisfies both conditions “A or B.”

With the widespread application of electric vehicles (EV) and hybrid electric vehicles (HEV), people are paying more attention to the vehicle usage time and usage costs. Therefore, the cycle life of secondary batteries, which are energy storage devices for vehicles, has naturally become one of the performance focuses of attention in the field. As expected, secondary batteries have excellent cycle performance and long battery life. This not only reduces user usage costs, but also means less resource consumption.

The solid electrolyte interface (SEI) film on the surface of the electrode plate plays an important role in improving the cycle performance of secondary batteries. The production of SEI films consumes electrolyte (or electrolyte ions, i.e. active ions or charge carrier ions) in the electrolyte. Therefore, if the SEI film is repeatedly damaged and regenerated during cycling, the active ion transport kinetics may decrease, leading to electrolyte depletion and cell performance dive.

However, currently commonly used positive and negative electrode active materials all change in volume to varying degrees during the cycle process, which affects the integrity and stability of the SEI layer and reduces battery performance. In particular, in the case of silicon-based anode active materials, the volume change is clear (change rate is 100% to 300%), making the above problem more prominent.

The industry pursues an SEI film layer that can adapt to changes in the volume of the material and maintain its integrity, which typically involves adding additives to the electrolyte or coating the surface of the active material or electrode plate. However, the SEI layer obtained by this method does not adapt well to changes in material volume, so battery performance cannot be significantly improved. As can be seen from the above, existing methods cannot effectively solve the interface problem caused by changes in the volume of the material.

In addition, it challenges the careful balance between cycle performance and storage performance. It is known in the art that good storage performance and long cycle life have different or even opposing requirements for SEI films. In terms of cycle life, relatively flexible and thin SEI is advantageous because it can adapt to the volume change of the cathode material, consumes less during repeated forming processes, and has a low interfacial impedance. On the other hand, for shelf life, non-porous and rigid SEI is advantageous because it can prevent electrolyte penetration and current leakage. However, during cycling, this thick and inflexible SEI cracks when the volume of the anode material changes, consuming additional electrolyte and affecting ion transport, resulting in a relatively low initial capacity and poor magnification performance.

However, secondary batteries desired in the art must have good overall performance, that is, good cycle performance and storage performance.

The object of the present invention is to provide a secondary battery with balanced overall performance, that is, good cycle performance and storage performance. Another object of the present invention is to provide a method for manufacturing a secondary battery. The secondary battery of the present invention has good overall performance, with smaller battery internal resistance after several cycles, longer cycle life, and better storage performance.

Hereinafter, the secondary battery, battery module, battery pack, and electric device of the present invention will be described with appropriate reference to the attached drawings.

Secondary battery and method of manufacturing the same

In one embodiment of the present invention, the present invention provides a secondary battery, wherein the secondary battery includes a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or germanium. Without being bound by any theory, by including an interfacial passivator in at least one of the positive electrode material layer, the electrolyte, and the negative electrode material layer, the secondary battery has a beneficial effect when active ion intercalation occurs in the negative electrode material during at least one charging process after being newly manufactured. By creating a ternary layer, the performance of the electrode plate and battery is improved.

In this specification, depending on the type of secondary battery, the active ions may be lithium ions or sodium ions. In other words, the active ion of a lithium ion secondary battery is lithium ion, and the active ion of a sodium ion secondary battery is sodium ion.

In some embodiments, the surface of the cathode material layer has an A-D-E ternary layer, wherein A is selected from an alkali metal element and is different from E, and D is silicon or carbon; The A-D-E ternary layer is formed when the interface passivator acts on the surface of the negative electrode material layer during at least one charging process of the secondary battery. The secondary battery of the present invention has a ternary layer on the surface of the negative electrode material layer, which stabilizes the negative electrode interface and can adapt to volume changes, thereby improving the performance of the electrode plate and battery, especially carefully balancing cycle performance and storage performance. can be implemented. Additionally, as the number of charge/discharge cycles increases, the advantages of the secondary battery of the present invention will be further emphasized, and in particular, battery impedance is significantly reduced, and battery cycle life and storage performance are improved (e.g., cycle life especially at high temperatures). and after storage, capacity retention rate is improved).

In this specification, “three-way layer” and similar expressions have the same or similar meaning and can be used interchangeably.

In some embodiments, the secondary battery is a lithium ion secondary battery or a sodium ion secondary battery. In this case, the interface passivator of the present invention or the three-dimensional layer can significantly improve cycle performance, impedance, etc. In some embodiments, the secondary battery is a lithium ion secondary battery.

In some embodiments, the interfacial passivator is a non-transition metal compound with an atomic number no greater than 20. These compounds may be organic or inorganic. The inventors found that it is relatively ideal to use a compound of a metal element with an atomic number not greater than 20 as an interface passivator, especially in lithium ion secondary batteries. In particular, it is desirable to select a metal compound whose activity is lower than that of the active ion of the secondary battery as the interface passivator. Without being bound by theory, these interfacial passivators are easy to generate electrons in electrochemical reactions, so it is easy to create a ternary layer. In comparison, it is difficult to achieve performance improvement in transition metal compounds in certain cases, which may be because transition metal atoms contain many empty orbitals, which are not helpful in forming a ternary layer and can strengthen the interfacial reaction.

As used herein, the term "transition metal" has a meaning known in the art and generally includes metal elements in the d-block and ds-block of the Periodic Table of the Elements (d-block elements include elements of periods IIIB to VIIB and VIII). is included, excluding lanthanide and actinide elements; the ds-block includes elements from groups IB to IIB of the periodic table).

In some embodiments, in the interfacial passivator, the metal cation moiety has a valence of 2-5. In some embodiments, the interfacial passivator may be selected from at least one of lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, gallium, and germanium compounds; Optionally, it may be selected from at least one of beryllium, magnesium, potassium, calcium, aluminum, gallium, and germanium compounds.

In some embodiments, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum, and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum. By selecting a compound containing the metal element, the effect of the interfacial passivation layer can be further improved, thereby improving the performance of the secondary battery more effectively.

In some embodiments, the interfacial passivator is selected from a combination of two or three of magnesium, aluminum, and calcium compounds. By introducing a combination of these interface passivators, battery internal resistance, cycle, and storage performance can be further improved.

In some embodiments, the interfacial passivator is selected from at least one of substituted or unsubstituted C _1-20 carboxylates, and the substituents are C _1-6 alkyl, C _2-6 cycloalkyl, hydroxyl, amino, oxo group, acyl, C _1-6 alkylthio, phenyl, benzoylthio, phenylthio and phenoxy; iminoates; enoates; phosphate; sulfate; sulfonimide salt; sulfonate; benzoate; phthalate; acetylacetonate; inorganic oxoates; and one or more of double salts containing two or more of the above non-transition metal cations.

In some embodiments, optionally, the interfacial passivator is calcium propionate, calcium stearate, calcium acetate, calcium cyclohexanebutyrate, calcium formate, calcium DL-malate, calcium glycolate, calcium 3-methyl-2-oxobutyrate. , calcium levulinate, calcium 2-ethylhexanoate, 2-hydroxy-4-(methylthio)butyrate, calcium DL-glycerate, aluminum stearate, aluminum monostearate, aluminum acetate base, aluminum terephthalate, aluminum acetate. , aluminum oxalate, aluminum distearate, aluminum lactate, magnesium stearate, magnesium lactate, magnesium oxalate, magnesium acetate, magnesium citrate, magnesium valproate, magnesium 2-ethylhexanoate, magnesium 2-ethylbutyrate, magnesium phenoxylate, Calcium bis(nonafluorobutylsulfonyl)imide, calcium bis(fluorosulfonyl)imide, calcium bis(trifluoromethylsulfonyl)imide, magnesium bis(trifluoromethylsulfonyl)imide, Calcium methanesulfonate, calcium 2,5-dihydroxybenzenesulfonate, calcium trifluoromethanesulfonate, calcium dobesylate, magnesium trifluoromethanesulfonate, aluminum tris(trifluorosulfonate), calcium benzoate. Acetylate, Calcium Phthalate, Calcium 4-aminosalicylate, Calcium Acetylacetonate, Calcium Hexafluoroacetylacetonate, Beryllium Acetylacetonate, Magnesium Acetylacetonate, Magnesium Bis(2,4-Pentanedione), Magnesium Trifluoride Roacetylacetonate, magnesium hexafluoroacetylacetonate, aluminum acetylacetonate, aluminum tris(trifluoro-2,4-pentanedione), calcium metaborate, calcium nitrate, aluminum metaphosphate, aluminum perchlorate, dihydrogen phosphate Aluminum, aluminum hypophosphite, aluminum phosphate, magnesium perchlorate, magnesium metaborate, magnesium nitrate, beryllium sulfate, calcium aluminate, triethyl aluminum, trioctyl aluminum, tri-n-butyl aluminum, dimethyl aluminum isopropoxide, tri( Hexadecyl)aluminum, magnesium dicene, di-n-butylmagnesium, n-butylethylmagnesium, bis(ethylcyclopentadienyl)magnesium, bis(pentadiene methylcyclopentadienyl)magnesium, bis(cyclopentadienyl) Magnesium, bis(n-propylcyclopentadienyl)magnesium, bis(ethylcyclopentadienyl)magnesium, bis(2-(2-hydroxyphenyl)pyridine)beryllium, calcium bis(pentamethylcyclopentadienyl)tetra Hydrofuran, aluminum isopropoxide, aluminum ethoxide, aluminum tert-butoxide, aluminum sec-butoxide, aluminum n-butoxide, aluminum sec-butoxide, bis(2-ethylate hexanoic acid) aluminum hydroxy , magnesium methoxide, magnesium ethoxide, magnesium tert-butoxide, magnesium aluminum silicate, calcium methacrylate, calcium sorbate (2,4-hexadienoic acid), aluminum acrylate, magnesium acrylate, calcium phytate, bis( 2-ethylhexyl) is selected from at least one of hemicalcium phosphate, aluminum diethylphosphinate, magnesium lauryl sulfate, propiophenone calcium acetonate, and calcium acetonate.

In some embodiments, optionally, the interfacial passivator is selected from at least one of fluorosulfonimide salts, acetylacetonates, and inorganic oxoates. In some embodiments, the inorganic oxo acid salt is selected from at least one of metaboric acid, nitric acid, metaphosphoric acid, perchloric acid, phosphoric acid, hypophosphorous acid, sulfuric acid, and aluminic acid. In some embodiments, the interfacial passivator is selected from at least one of fluorosulfonimide salts, acetylacetonate, fluoroacetylacetonate, nitrate, phosphate, perchlorate, and sulfate.

In some embodiments, optionally, the interfacial passivator is calcium bis(nonafluorobutylsulfonyl)imide, calcium nitrate, tris(trifluoro-2,4-pentanediyl)aluminum, aluminum phosphate, magnesium. It is selected from at least one of hexafluoroacetylacetonate, magnesium perchlorate, beryllium acetylacetonate and beryllium sulfate.

By selecting the interface passivator, it is possible to reduce the resistance of the secondary battery and achieve a careful balance between cycle life and storage performance.

In some embodiments, the interfacial passivator is blended into at least one of the anode material layer (or anode slurry), the cathode material layer (or cathode slurry), and the electrolyte solution. By adding the interfacial passivator directly to the battery system by blending, it is more advantageous to form the ternary layer.

In this specification, “blending” means that the interfacial passivator is directly doped and mixed and spread (or dispersed) in a slurry or electrolyte solution. Blending does not include covering.

In some embodiments, the A-D-E ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Li-C-Ca, Li-C-Mg, Li-C -Be, Li-C-Al, Na-Si-Ca, Na-Si-Mg, Na-Si-Be, Na-Si-Al, Na-C-Ca, Na-C-Mg, Na-C-Be , Na-C-Al ternary hierarchy, and combinations thereof. In some embodiments, optionally, the A-D-E ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Na-Si-Ca, Na-Si-Mg, It is selected from Na-Si-Be, Na-Si-Al ternary layer, and combinations thereof. By including the ternary interface passivation layer in a secondary battery, battery impedance, cycle life, and storage performance can be effectively improved.

In some embodiments, the ternary layer is formed by an interfacial passivator acting on the surface of the anode material during at least one charging cycle of the secondary battery. In some embodiments, the ternary layer is formed during one to three charging cycles of the secondary battery, optionally one to two charging cycles, and more optionally one charging cycle.

In some embodiments, before the at least one charge, the positive electrode material layer contains 0.001% to 20% by weight, optionally 1% to 10% by weight of the interface passivator, based on the total weight of the positive electrode material layer. Includes.

In some embodiments, before the at least one charge, based on the total weight of the negative electrode material layer, the negative electrode material layer contains 0.001% to 20% by weight, optionally 0.05% to 5% by weight of the interface passivator. Includes.

In some embodiments, prior to the at least one charge, the electrolyte comprises 0.001% to 20% by weight, optionally 0.1% to 5% by weight of the interfacial passivator, based on the total weight of the electrolyte. do. In some embodiments, optionally, prior to the at least one charge, the electrolyte solution contains 0.2% to 5% by weight, optionally 0.3% to 5% by weight of the interfacial passivator, based on the total weight of the electrolyte solution. Includes.

By controlling the passivator content within the above range, battery performance can be further improved. If the content is too low, an effective ternary interface passivation layer cannot be formed; If the content is too high, a ternary phase may be generated in the bulk phase of the electrode material layer, lowering the energy density of the cell.

In some embodiments, it is advantageous for the anode material layer to include the interfacial passivator. At this time, since the amount of interfacial passivator added is small, the expected purpose is achieved while reducing the impact on electrolyte components or performance.

In some embodiments, the negative electrode active material layer includes a silicon-based negative electrode active material or a carbon-based negative electrode active material. In particular, in some embodiments, the negative electrode material layer includes a silicon-based negative electrode active material. When using a negative electrode material with a large change in volume, the advantage of including the ternary layer of the present invention in a secondary battery is particularly significant. When the negative electrode material layer includes a silicon-based negative electrode material (even composed of a silicon-based negative electrode active material), it is particularly advantageous to add the interfacial passivator of the present invention to such a secondary battery system.

In some embodiments, the D50 of the negative electrode active material is 1 μm to 20 μm, optionally 2 μm to 10 μm. By using a material having the above D50, the interfacial passivating effect of the ternary layer of the present invention can be effectively exerted, thereby significantly improving the performance of the secondary battery, and achieving a balance between the ease of manufacturing of the electrode plate and superior performance. By using a material whose D50 is within the above range, excessive interfacial activity due to excessive material specific surface area can be prevented, which is advantageous for improving the desired performance of the interfacial passivation layer; At the same time, inhibition of active ion movement can be prevented, which is advantageous in improving the overall performance of the battery.

In some embodiments, the negative electrode active material has a Span value of 0.9 to 1.8, optionally 0.9 to 1.2;

ego,

D90, D10 and D50 represent the corresponding particle sizes when the cumulative distribution percentage is 90%, 10% and 50%, respectively. In this specification, the units of D90, D10 and D50 are μm. By selecting a negative electrode active material with a Span value within the above range, it is advantageous for the material to have relative interfacial stability and is helpful in implementing the effect of improving battery performance.

In this specification, “Span value” characterizes the width of the particle size distribution of a material. The Span value is a dimensionless number defined above. By using a negative electrode material having a Span value within the above range, it is advantageous for the material to have relative interfacial stability and is helpful in implementing the effect of improving battery performance.

In some embodiments, the D50 of the negative electrode active material is 1 μm to 20 μm, and the Span value is 0.9 to 1.8. In some other embodiments, the D50 of the negative electrode active material is preferably 3 μm to 10 μm, and the Span value is preferably 0.9 to 1.2.

A second aspect of the present invention provides a secondary battery, the secondary battery comprising:

i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and

ii) It is manufactured through the step of performing at least one charge/discharge cycle on a secondary battery that has not gone through the above cycle.

A third aspect of the present invention provides a method for manufacturing a secondary battery, the method comprising:

i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and

ii) performing at least one charge/discharge cycle on the secondary battery that has not gone through the cycle to form an A-D-E ternary layer to obtain the secondary battery; A is selected from an alkali metal element and is different from E, and D is silicon or carbon.

The secondary battery finally manufactured by the above method is a secondary battery provided with a ternary passivation layer on the surface of the negative electrode material layer, and has improved impedance, cycle life, and storage performance.

In some embodiments, step i) includes a) providing an anode slurry, a cathode slurry, and an electrolyte solution, wherein at least one of the anode slurry, the cathode slurry, and the electrolyte solution is blended with an interfacial passivator.

In some embodiments, step i) includes: b) coating the positive electrode slurry and the negative electrode slurry on at least one surface of the positive electrode current collector and the negative electrode current collector, respectively, to obtain a positive electrode plate and a negative electrode plate; and assembling the electrolyte into a secondary battery that has not been cycled.

Without being bound by theory, when the negative electrode material layer includes an interface passivator, when performing the at least one charge/discharge cycle, the interface passivator acts directly on the negative electrode material layer to form a three-dimensional layer; When the positive electrode material layer and/or the electrolyte solution include an interface passivator, when performing the at least one charge/discharge cycle, the interface passivator moves to the surface of the negative electrode material layer under the action of voltage to create a three-dimensional layer. For example, the interface passivator, the active ions of the secondary battery, and the negative electrode active material form the ternary layer under the action of voltage. The present invention improves battery performance by forming a ternary layer on the surface of the negative electrode material layer.

In some embodiments, the at least one charge/discharge cycle in step ii) is performed at a voltage of 3V to 4.3V.

In some embodiments, step ii) is a chemical step.

In this specification, the term "chemical formation" has a meaning known in the art. Generally, when a newly manufactured secondary battery is first charged, intercalation and deintercalation of lithium ions occur to activate the negative electrode active material. This means forming a passivation layer, for example, a solid electrolyte interface film (SEI film), on the surface of the cathode material layer.

In some embodiments, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum, and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum.

In some embodiments, before the at least one charge, the positive electrode material layer contains 0.001% to 20% by weight, optionally 1% to 10% by weight of the interface passivator, based on the total weight of the positive electrode material layer. Includes.

In some embodiments, before the at least one charge, based on the total weight of the negative electrode material layer, the negative electrode material layer contains 0.001% to 20% by weight, optionally 0.05% to 5% by weight of the interface passivator. Includes.

In some embodiments, prior to the at least one charge, the electrolyte comprises 0.001% to 20% by weight, optionally 0.1% to 5% by weight of the interfacial passivator, based on the total weight of the electrolyte. do.

In some embodiments, the interfacial passivator is added to the positive plate material slurry, negative plate material slurry, or electrolyte solution in a blended (or mixed) manner.

The cathode material slurry includes a cathode active material, an interfacial passivator, a solvent, and optionally additives. In some embodiments, based on the dry weight of the cathode material slurry, the cathode material slurry includes 0.001% to 20% by weight, optionally 1% to 10% by weight, of an interfacial passivator.

The anode material slurry includes an anode active material, an interfacial passivator, a solvent, and optionally additives. In some embodiments, based on the dry weight of the anode material slurry, the anode material slurry includes 0.001% to 20% by weight, optionally 0.05% to 5% by weight of an interfacial passivator.

By using the interface passivator within the above content range, the effect of effectively forming a ternary layer on the surface of the negative electrode material layer is to passivate the interface, protect the interface, and improve the performance of the secondary battery.

In some embodiments, the negative electrode slurry includes a negative electrode active material. The negative electrode active material includes a silicon-based negative electrode active material or a carbon-based negative electrode active material. In particular, in some embodiments, the negative electrode slurry includes a silicon-based negative electrode active material. In the case of anode active materials with large volume changes, the advantages of the interfacial passivator of the present invention and the ternary layer formed therefrom are particularly significant.

In addition, the following describes each component of the secondary battery excluding the interface passivator.

[Anode plate]

The positive electrode plate includes a positive electrode current collector and a positive electrode material layer installed on at least one surface of the positive electrode current collector, and the positive electrode material layer includes a positive electrode active material.

Illustratively, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode film layer is installed on one or both of the two opposing surfaces of the positive electrode current collector.

In some embodiments, the positive electrode current collector may use a metal foil or a composite current collector. For example, the metal foil can be aluminum foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one side of the polymer material base layer. Composite current collectors are made by combining metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) with a polymer material substrate (e.g., polypropylene (PP), polyethylene terephthalate (PET), polyester). It can be formed on substrates such as butylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

In some embodiments, the positive electrode active material may be a battery positive active material known in the art. As an example, the positive electrode active material may include at least one of olivine-structured lithium-containing phosphate, lithium transition metal oxide, and each of these modified compounds. However, the present invention is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used individually or in combination of two or more types. Here, examples of lithium transition metal oxides include lithium cobalt oxide (e.g. LiCoO ₂ ), lithium nickel oxide (e.g. LiNiO ₂ ), lithium manganese oxide (e.g. LiMnO ₂ , LiMn ₂ O ₄ ), lithium nickel cobalt oxide, lithium. _Manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide ₍ e.g. LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (may be abbreviated as _{NCM 333} ), LiNi _0.5 Co _{0.2 Mn 0.3} O _{2 (} may be abbreviated as NCM ₅₂₃ ) _, LiNi _{O. 5 Co 0.25 Mn 0.25 O 2 (may be abbreviated as NCM 211 ) , LiNi 0.6 Co 0.2 Mn 0.2 O 2 (} NCM _{622 ) (} may be abbreviated _{as NCM 811} ), LiNi _{0.8 Co 0.1 Mn 0.1 O 2} (may be abbreviated as NCM ₈₁₁ ), lithium nickel _{cobalt aluminum} oxide ₍ e.g. LiNi _0.85 Co _0.15 Al _{0 . 05} O ₂ ) and its modified compounds, etc. Examples of lithium-containing phosphates with an olivine structure include lithium iron phosphate (e.g., LiFePO ₄ (may be abbreviated as LFP)), lithium phosphate It includes, but is not limited to, at least one of a composite material of iron and carbon, lithium manganese phosphate (e.g., LiMnPO ₄ ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. .

In the secondary battery of the present invention, optionally, the positive electrode active material changes in the volume of battery active ions (e.g., lithium ions, sodium ions, or potassium ions) during the intercalation-deintercalation process, and/or the material interface changes in the electrolyte solution. It is selected from materials that cause catalysis. In some embodiments, the positive electrode active material is lithium iron phosphate (LFP), lithium iron manganese phosphate (LFMP), lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel selected from one or more of cobalt aluminum oxide, lithium-rich materials, sodium-oxygen compounds or potassium-oxygen compounds, and compounds obtained by adding other metals to the compounds, wherein the other metals are transition metals and/or beryllium, magnesium, selected from one or more of non-transition metals other than calcium and aluminum. However, those skilled in the art recognize that the present invention is not limited to these materials.

In some embodiments, the positive electrode film layer may optionally further include a binder. As an example, the binder may be polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoro propylene-tetrapolymer. It may include at least one of fluoroethylene terpolymer, tetrafluoroethylene-hexafluoro propylene copolymer, and fluorine-containing acrylate resin.

In some embodiments, the positive electrode film layer may optionally further include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In some embodiments, the positive electrode plate is prepared by dispersing components for manufacturing the positive electrode plate, such as a positive electrode active material, a conductive agent, a binder, and any other components, in a solvent (e.g., N-methylpyrrolidone) to form a positive electrode slurry, and the positive electrode slurry It can be manufactured by coating a positive electrode current collector and then obtaining a positive electrode plate through processes such as drying and cold pressing.

[Cathode plate]

The negative electrode plate includes a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

As an example, the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode film layer is provided on one or both of the two opposing surfaces of the negative electrode current collector.

In some embodiments, the negative electrode current collector may use a metal foil or a composite current collector. For example, the metal foil can be copper foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one side of the polymer material base layer. Composite current collectors are made by combining metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) with a polymer material substrate (e.g., polypropylene (PP), polyethylene terephthalate (PET), polyester). It can be formed on base materials such as butylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

In some embodiments, the negative electrode active material may be a negative electrode active material for batteries known in the art. As an example, the negative electrode active material may include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate. The silicon-based material may be selected from at least one of simple element silicon, silicon oxide (silicon oxide, silicon monoxide, etc.), silicon carbon composite, silicon nitrogen composite, and silicon alloy. The tin-based material may be selected from at least one of elemental tin, tin oxide (tin oxide), and tin alloy. However, the present invention is not limited to these materials, and other conventional materials that can be used as negative active materials for batteries can also be used. These negative electrode active materials can be used individually or in combination of two or more types.

In the secondary battery according to the present invention, optionally, the negative electrode active material changes the volume of battery active ions (e.g., lithium ions, sodium ions, potassium ions, etc.) during the intercalation-deintercalation process, and/or the material interface. It is selected from materials that cause a catalytic effect in the electrolyte solution. In some embodiments, the negative electrode active material is selected from silicon-based negative electrode materials or carbon-based negative electrode materials. In some embodiments, optionally, the negative electrode active material is graphite, soft carbon, hard carbon, mesocarbon microspheres, carbon fiber, carbon nanotube, simple element silicon, silicon-oxygen compound, silicon-carbon composite, and other materials of the above materials. It is selected from one or more of the compounds obtained by adding a metal, wherein the other metal is selected from one or more of transition metals and/or non-transition metals other than beryllium, magnesium, calcium and aluminum. However, those skilled in the art recognize that the present invention is not limited to these materials.

In some embodiments, the negative electrode active material is selected from silicon-based negative electrode materials. In some embodiments, the negative electrode active material is selected from one or more of simple element silicon, silicon-oxygen compounds, and silicon-carbon composites.

In some embodiments, the negative electrode film layer may optionally further include a binder. The binder is styrenebutadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and polymethacrylic acid (PMAA). , acrylate, and carboxymethyl chitosan (CMCS).

In some embodiments, the negative electrode film layer may optionally further include a conductive agent. The conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

In some embodiments, the negative electrode film layer may optionally further include other auxiliaries such as thickeners (eg, carboxymethyl cellulose sodium (CMC-Na)).

In some embodiments, the negative electrode plate is formed by dispersing components for manufacturing the negative electrode plate, such as the negative electrode active material, conductive agent, binder, and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; The negative electrode slurry is coated on the negative electrode current collector and can be manufactured through processes such as drying and cold pressing.

[Electrolyte]

Electrolyte plays a role in transferring ions between the positive and negative plates. The present invention does not specifically limit the type of electrolyte, so it can be selected as needed. For example, the electrolyte can be a liquid, a gel, or both solids.

In some embodiments, the electrolyte is in a liquid state and includes an electrolyte salt and a solvent.

In the present invention, the type of electrolyte salt is not particularly limited and can be selected according to actual needs. In some embodiments, the electrolyte salt is lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium bisfluoro. Sulfonylimide (LiFSI), lithium bistrifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium dioxalate borate, lithium difluorophosphate, lithium di Fluoroxalate borate (LiBOB), lithium difluoro dioxalate phosphate, lithium tetrafluoroxalate phosphate and LiN(C _x F _2x +1SO ₂ )(C _y F _2y +1SO ₂ ), where x, y is a natural number). The above is only an example of electrolyte salts used in lithium ion secondary batteries, and the present invention is not limited thereto. In the case of a secondary battery having different active ions, the electrolyte salt is also not specifically limited and can be selected according to actual needs.

In the present invention, the type of organic solvent of the electrolyte is not particularly limited and can be selected according to actual needs. In some embodiments, the organic solvent may include one or more of chain carbonates, cyclic carbonates, carboxylates, and ethers. The present invention does not specifically limit the types of chain carbonate, cyclic carbonate, carboxylate, and ether, and may be selected according to actual needs. In some embodiments, optionally, the organic solvent is diethyl carbonate, dipropyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, ethylene propyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, methyl It may include one or more of formate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, tetrahydrofuran, dimethyl ether, diethyl ether, and ethylene glycol dimethyl ether.

In some embodiments, the electrolyte solution may optionally further include additives. By way of example, the additive may include a negative film forming additive, a positive film forming additive, and an additive that can improve specific performance of the battery, such as an additive to improve the overcharge performance of the battery, and an additive to improve the high or low temperature performance of the battery. Additional additives may be included.

In some embodiments, the electrolyte solution additive is a cyclic carbonate compound containing an unsaturated bond, a halogen-substituted cyclic carbonate compound, a sulfate compound, a sulfite compound, a sultone compound, a disulfonic acid compound, a nitrile compound, an aromatic compound, an isocyanate compound, It is selected from at least one of a phosphazene compound, a cyclic anhydride compound, a phosphite compound, a phosphate compound, a borate compound, and a carboxylate compound.

[Separator]

In some embodiments, the secondary battery further includes a separator. In the present invention, there is no particular limitation on the type of separator, and a separator with a known porous structure having excellent chemical and mechanical stability can be selected.

In some embodiments, the material of the separator may be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film, but is not particularly limited thereto. When the separator is a multilayer composite film, the material of each layer may be the same or different, but is not particularly limited thereto.

In some embodiments, the positive electrode plate, negative electrode plate, and separator may be manufactured into an electrode assembly through a winding process or a lamination process.

In some embodiments, the secondary battery may include external packaging. The outer packaging is for packaging the electrode assembly and electrolyte.

In some embodiments, the external packaging of the secondary battery may be a hard case such as a hard plastic case, an aluminum case, a steel case, etc. The external packaging of a lithium-ion battery may be a soft package such as a bag-type soft package. The material of the soft package may be plastic, and examples of plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

The present invention does not specifically limit the shape of the secondary battery, and it may be cylindrical, rectangular, or any other shape. For example, Figure 1 shows one exemplary rectangular structure secondary battery 5.

In some embodiments, referring to Figure 2, the outer packaging may include a case 51 and a cover plate 53. Here, the case 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate are surrounded to form a receiving cavity. The case 51 has an opening that communicates with the receiving cavity, and the cover plate 53 can be installed to cover the opening to seal the receiving cavity. The positive electrode plate, negative electrode plate, and separator may be formed into the electrode assembly 52 through a winding process or a lamination process. An electrode assembly 52 is packaged within the receiving cavity. The electrolyte solution permeates the electrode assembly 52. The number of electrode assemblies 52 included in the secondary battery 5 may be one or more, which can be selected by a person skilled in the art according to specific needs.

In some embodiments, the secondary battery may be assembled into a battery module, and the number of ion batteries included in the battery module may be one or more, and the specific number may be selected by a person skilled in the art depending on the application and capacity of the battery module.

3 shows one exemplary battery module 4. Referring to FIG. 3 , in the battery module 4, a plurality of secondary batteries 5 may be sequentially arranged and installed along the longitudinal direction of the battery module 4. Of course, it may also be arranged according to any other manner. Additionally, the plurality of secondary batteries 5 can be fixed through a fastener.

Optionally, the battery module 4 may further include a case having an accommodating space, and a plurality of secondary batteries 5 are accommodated in the accommodating space.

In some embodiments, the battery modules may also be assembled into a battery pack, and the number of battery modules included in the battery pack may be one or more, and the specific number may be selected by a person skilled in the art according to the application and capacity of the battery pack. .

4 and 5 show one exemplary battery pack 1. Referring to FIGS. 4 and 5 , the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper box (2) and a lower box (3), where the upper box (2) can be installed to cover the lower box (3) and is sealed to accommodate the battery module (4). Space can be formed. A plurality of battery modules 4 may be arranged in the battery box according to any method.

In addition, the present invention also provides an electrical device. The electric device includes one or more of a secondary battery, a battery module, or a battery pack provided by the present invention. The secondary battery, battery module, or battery pack may be used as a power source for the device or may be used as an energy storage unit for the electric device. The electric devices include mobile devices (e.g. cell phones, laptop computers, etc.), electric vehicles (e.g. pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric vehicles, etc. This may be, but is not limited to, trains, ships and satellites, energy storage systems, etc.

The electric device may select a secondary battery, battery module, or battery pack depending on usage needs.

6 shows one example electrical device. The electric device may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to satisfy the electric device's requirements for high power and high energy density of secondary batteries, a battery pack or battery module can be used.

As another example, the device may be a cell phone, tablet computer, laptop computer, etc. Since the device typically needs to be light and thin, a secondary battery can be used as a power source.

Example

Hereinafter, embodiments of the present invention will be described. The embodiments described below are illustrative and are only for interpreting the present invention, and should not be construed as limiting the present invention. If specific techniques or conditions are not specified in the examples, they are performed according to techniques, conditions, or product specifications described in literature in the art. If the manufacturer of the reagents or instruments used is not specified, they are all commercially available products.

The secondary batteries of the Examples and Comparative Examples of the present invention were all manufactured according to the following method.

1. Manufacturing of positive plate

According to Table 1 below, the positive electrode active material, acetylene black as a conductive agent, and polyvinylidene fluoride (PVDF) as a binder were dissolved in N-methylpyrrolidone (NMP) as a solvent at a weight ratio of 90:5:5, ( (if present) The interface passivator of the present invention was added here, stirred sufficiently and mixed uniformly to obtain a positive electrode slurry. Thereafter, the positive electrode slurry was uniformly applied to the aluminum foil of the positive electrode current collector at a loading amount of 0.2 mg/mm ² , dried, cold pressed, and cut into 57,000 mm ² positive electrode plates.

In each table below, when the anode material layer or the cathode material layer includes an interface passivator, the content of the interface passivator is weight% (wt%) based on the dry weight of the anode material layer or the cathode material layer, respectively; When the electrolyte includes an interfacial passivator, the content of the interfacial passivator is expressed in weight percent based on the total weight of the electrolyte.

positive electrode active material interface passivator interface Passivator quantity LFP anode Lithium iron phosphate (LFP) - - Ni0 anode LiNi _{0 . 8} Co _{0 . 1} Mn _{0 . 1} O ₂ (NC811) - - Ni1 anode NCM811 Beryllium Acetylacetonate 5wt% Ni2 anode NCM811 Nickel Acetylacetonate 5wt% Ni3 anode NCM811 Beryllium Acetylacetonate 0.005wt% Ni4 anode NCM811 Beryllium Acetylacetonate 1wt% Ni5 anode NCM811 Beryllium Acetylacetonate 10wt% Ni6 anode NCM811 Beryllium Acetylacetonate 15wt% Ni7 anode NCM811 Beryllium Acetylacetonate 20wt%

2. Manufacturing of cathode plate

According to Table 2 below, each negative electrode active material, acetylene black as a conductive agent, styrene-butadiene rubber (SBR) as a binder, and sodium carboxymethylcellulose (CMC) as a thickener were mixed in deionized water as a solvent at a weight ratio of 90:4:4:2. After dissolving in , the interfacial passivator of the present invention (if present) was added thereto, stirred sufficiently and mixed uniformly to obtain a cathode slurry. Afterwards, the negative electrode slurry was uniformly applied at least once to the copper foil of the negative electrode current collector at a loading amount of 0.12 mg/mm ² , dried, cold pressed, and cut into 60,000 mm ² negative electrode plates.

*Here, “/” means “and”, that is, “calcium bis(nonafluorobutylsulfonyl)imide/magnesium perchlorate” is “calcium bis(nonafluorobutylsulfonyl)imide and magnesium perchlorate” means. The meaning of similar expressions below is also the same.

3. Preparation of electrolyte solution

According to Table 3 below, in an argon atmosphere (H ₂ O<0.1ppm, O ₂ <0.1ppm) glove box, the organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were uniformly mixed at a volume ratio of 3/7. After mixing, 12.5% by weight of hexafluorophosphate (LiPF ₆ ) was added to the mixed organic solvent and dissolved in the electrolyte salt, followed by 1% by weight of 1,3-propanesultone (PS) and 0.5% of ethylene sulfate ( DTD), 0.5% vinylene carbonate (VC) and 2% fluoroethylene carbonate (FEC) are added as additives, then the interfacial passivator of the present invention (if present) is added and stirred uniformly to form an electrolyte solution. got it All weight percentages are based on the total weight of the electrolyte.

interface passivator interface Passivator quantity EL0 electrolyte - - EL1 electrolyte Magnesium hexafluoroacetylacetonate 1wt% EL2 electrolyte Tris(trifluoro-2,4-pentanediyl)aluminum 2wt% EL3 electrolyte Manganese Bis(trifluoromethanesulfonyl)imide 1wt% EL4 electrolyte Magnesium hexafluoroacetylacetonate/tris(trifluoro-2,4-pentanediyl)aluminum 1wt%/1wt% EL5 electrolyte Magnesium hexafluoroacetylacetonate 0.005wt% EL6 electrolyte Magnesium hexafluoroacetylacetonate 0.3wt% EL7 electrolyte Magnesium hexafluoroacetylacetonate 5wt% EL8 electrolyte Magnesium hexafluoroacetylacetonate 10wt% EL9 electrolyte Magnesium hexafluoroacetylacetonate 20wt%

4. Manufacturing of secondary batteries

(1) According to Table 4 below, the positive electrode plate, separator, and negative electrode plate are stacked in that order, the separator is placed between the positive and negative electrode plates, brought into close contact to serve as a separation, and then wound to obtain an electrode assembly; After the electrode assembly was placed in a battery case and dried, an electrolyte solution was injected at an amount of 2.4 g/Ah to obtain a newly manufactured secondary battery.

(2) Formation of the secondary battery: The formation is performed at closed atmospheric pressure, the formation temperature is 45°C, the current is 0.1C, the voltage is 3 to 4.3V, and then left to stand, and finally, the embodiments and comparative examples of the present invention are formed. A secondary battery was manufactured.

5. Test

5.1 Detection of three-way hierarchy

Ternary layers can be detected using conventional means in the art, such as solid-state nuclear magnetic resonance, X-ray powder diffraction (XRD), X-ray electron spectroscopy (XPS), Raman spectroscopy, or a combination of the above.

5.2 Initial secondary battery internal resistance and secondary battery internal resistance after 1000 cycles

(1) Charge the secondary battery manufactured as above (hereinafter referred to as “new battery”) to 4.3V at 1C constant current at 45°C, and then charge at 4.3V constant voltage until the current reaches 0.05C or less. Then, the lithium ion battery was discharged to 3.0V at a constant current of 1C, which is one charge/discharge process (i.e., 1 cycle). In this way, 1000 cycles were repeated to obtain a secondary battery after 1000 cycles at 45°C (hereinafter referred to as “battery after 1000 cycles at 45°C”).

(2) At 25°C, both the new battery as above and the battery after 1000 cycles at 45°C were charged to 4.3V at a constant current of 1C, then charged at a constant voltage of 4.3V until the current reached 0.05C or less, and then Afterwards, it was discharged at 1C for 30 minutes, that is, the power amount of the secondary battery was adjusted to 50% of the battery state of charge (SOC). Afterwards, the positive and negative test leads of the TH2523A AC internal resistance tester (Tonghui Electronics) are contacted to the positive and negative electrodes of the secondary battery to be tested, respectively, and the battery internal resistance value is read through the internal resistance tester to determine the initial secondary battery internal resistance and The internal resistance of the secondary battery was recorded after 1000 cycles.

5.3 Capacity retention after 1000 cycles at 45°C

Wuhan Blue Electric was used in the above test. At 45°C, the secondary battery was charged to 4.3V at a 1C constant current, then charged at a 4.3V constant voltage until the current reached 0.05C or less, and then the lithium ion battery was discharged to 3.0V at a 1C constant current, which is With one charge/discharge process (i.e., 1 cycle, or first cycle), the discharge capacity was recorded after the first cycle. In this way, 1000 cycles were repeated, and the discharge capacity was recorded after the 1000th cycle. The capacity maintenance rate of the secondary battery after 1000 cycles was calculated according to the following formula.

Capacity retention rate of lithium-ion battery after 1000 cycles at 45℃ (%) = (discharge capacity after 1000th cycle/discharge capacity after first cycle)Х100%.

5.4 Capacity retention rate after storage at 60℃ for 300 days

At 25°C, the battery was charged at a 1C constant current until the voltage reached 4.3V, then charged at a 4.3V constant voltage until the current reached 0.05C, and then the lithium ion battery was discharged to 3.0V at a 1C constant current. , This is one charge/discharge process (i.e., 1 cycle, or first cycle), and the discharge capacity of the secondary battery was tested after the first cycle. Thereafter, the fully charged secondary battery was placed in an incubator at 60°C and stored for 300 days, and the discharge capacity was tested after 300 days of storage.

Capacity retention rate of lithium-ion battery after storage for 300 days at 60℃ (%) = (Discharge capacity after storage for 300 days/Discharge capacity after first cycle)Х100%.

The above test results are recorded in Tables 5 to 9 below.

number Initial secondary battery internal resistance
（ mΩ ） Secondary battery internal resistance after 1000 cycles (mΩ) Capacity retention rate after 1000 cycles at 45℃ (%) Capacity retention rate after storage at 60℃ for 300 days ( % ） Comparative example One 870 1049 28 26 Example One 781 1001 51 41 Example 2 796 1023 46 38 Example 3 1013 1315 15 13 Example 4 789 1011 49 39 Example 5 799 1025 47 38 Example 6 1021 1319 15 14

As can be seen from the table above, in Comparative Example 1, the secondary battery in which the positive electrode active material is LFP and the negative electrode active material is a silicon-carbon composite material does not include the interface passivator of the present invention, so the cycle life of the secondary battery is very poor. . In comparison, the secondary batteries of Examples 1 to 2 and 4 to 5 contain the interfacial passivator of the present invention, which can effectively improve capacity retention, lower battery impedance, and improve battery performance.

Without being bound by any theory, the reason for such poor cycle life in Comparative Example 1 is mainly because the silicon-carbon composite material contained in the negative electrode changes in volume during the lithium deintercalation-lithium intercalation process of the charge/discharge cycle. This is because rupture and regeneration of the interface components occur. After several cycles, the interfacial component thickens. Therefore, the secondary battery of Comparative Example 1 had a large secondary battery internal resistance after 1000 cycles; Additionally, the destruction and regrowth of the interface consumes active lithium, which also results in a rapid decrease in capacity retention over the course of the cycle. In addition, the high surface activity of a fully charged silicon-based anode results in excessive electrolyte consumption, so the capacity retention rate is low after storage at 60°C for 300 days. However, in the secondary battery of the present invention, the interface passivator included creates a ternary interface passivation layer at the interface between the cathode material layer and the electrolyte solution during the charge/discharge cycle process, so the reaction activity of the cathode interface is reduced. Additionally, as the number of cycles increases, the above advantages of the secondary battery of the present invention become more prominent.

In addition, from the data in the table above, the secondary battery of Example 3 contains a cobalt salt, and the secondary battery of Example 6 contains a manganese salt, but the same beneficial effects as Examples 1 to 2 and 4 to 5 can be achieved. There is none, and rather, it can be seen that the performance of the battery deteriorates.

number Initial secondary battery internal resistance ( mΩ ) Secondary battery internal resistance after 1000 cycles (mΩ) Capacity retention rate (%) after 1000 cycles at 45℃ Capacity retention rate after storage at 60℃ for 300 days ( % ) Comparative example 2 1010 1329 14 11 Example 7 901 1281 45 31 Example 8 921 1293 43 29 Example 9 1113 1411 10 8 Example 10 911 1289 44 30 Example 11 929 1302 41 27 Example 12 1121 1431 8 6

As can be seen from the table above, in Comparative Example 2, the secondary battery in which the positive electrode active material was NCM811 and the negative electrode active material was a silicon-carbon composite material had very poor battery cycle life. However, the secondary batteries of Examples 7 to 8 (the anode material layer included an interface passivator) and 10 to 11 (the electrolyte contained an interface passivator) showed significantly improved cycle performance.

Without being bound by any theory, the reason why the secondary battery of Comparative Example 2 has such a poor cycle life is that, in addition to the large volume change of the silicon-carbon material itself and the unstable structure of NCM811, the movement and catalytic action of transition metal ions are also interfacial instability. is one of the important influencing factors that cause

In Examples 7 to 8 and 10 to 11 of the present invention, by including an interfacial passivator, this polyvalent salt can form an interfacial passivation layer with silicon to stabilize the electrode-electrolyte interface. The secondary battery of the present invention can significantly improve the capacity retention rate, lower the impedance of the secondary battery, and improve the performance of the secondary battery.

On the other hand, the cathode of Example 9 contained a cobalt salt, and the electrolyte of Example 12 contained a manganese salt, which did not improve cycle performance.

number Initial secondary battery internal resistance
( mΩ ) Secondary battery internal resistance after 1000 cycles (mΩ) Capacity retention rate (%) after 1000 cycles at 45℃ Capacity retention rate after storage at 60℃ for 300 days ( % ) Comparative example 2 1010 1329 14 11 Example 13 991 1301 30 20 Example 14 1100 1400 20 13 Example 15 881 1231 51 41 Example 16 901 1283 47 31 Example 17 1106 1401 17 13 Example 18 900 1271 49 37 Example 19 910 1291 47 25 Example 20 1117 1421 11 9

In Comparative Example 2, when an unmodified silicon-carbon composite material is used in a secondary battery using NCM811 as the anode, the cycle life of the secondary battery is very poor.

The secondary batteries of Example 13, Examples 15 to 16, and 18 to 19 contain interfacial passivators of calcium, magnesium, aluminum, and beryllium to effectively improve capacity retention, lower battery impedance, and improve battery performance.

On the other hand, Examples 14, 17, and 20 contain salts of nickel, cobalt, and manganese, which deteriorates the performance of the secondary battery.

number Initial secondary battery internal resistance
( mΩ ) Secondary battery internal resistance after 1000 cycles (mΩ) Capacity retention rate (%) after 1000 cycles at 45℃ Capacity retention rate after storage at 60℃ for 300 days ( % ) Comparative example 2 1010 1329 14 11 Example 21 801 1203 56 47 Example 22 871 1236 51 44 Example 23 1092 1396 19 14 Example 24 902 1304 47 41 Example 25 973 1337 45 38 Example 26 1331 1513 14 9 Example 27 1931 2314 3 One

In Comparative Example 2, the interface passivator of the present invention was not used in a secondary battery whose cathode material was NCM811, and the cycle life of the secondary battery was poor.

Since the secondary batteries of Examples 21 and 22 contain organic or inorganic salts of calcium, magnesium, aluminum, and beryllium, they have significantly improved cycle performance. On the other hand, the secondary batteries of Examples 23 to 27 contained salts of nickel, cobalt, and manganese, which significantly deteriorated the performance of the secondary batteries. Here, in Examples 24 and 25, the performance may be deteriorated because the cathode contains cobalt, but the degree of deterioration can be slightly reduced because the anode and electrolyte solution contain beryllium, magnesium, or aluminum.

number Initial secondary battery internal resistance
( mΩ ) Secondary battery internal resistance after 1000 cycles (mΩ) Capacity retention rate (%) after 1000 cycles at 45℃ Capacity retention rate after storage at 60℃ for 300 days ( % ) Comparative example 2 1010 1329 14 11 Example 7 901 1281 45 31 Example 28 1001 1311 16 13 Example 29 798 1190 58 49 Example 30 821 1213 54 45

In Example 28, the surface of the negative electrode active material was coated with aluminum phosphate. In this case, there was a certain improvement in battery performance compared to Comparative Example 2, but the extent of the improvement was minimal. This coating layer has a stable bond and does not easily interact with the negative electrode active material to form a ternary layer as described in the present invention; On the other hand, the performance improvement effect of the coating layer is very limited because the interfacial layer inevitably ruptures even after several cycles.

By introducing the interface passivator calcium salt into the negative electrode material of Example 7, the overall performance of the secondary battery can be significantly improved compared to Comparative Example 2, and the extent of improvement is much higher than that of Example 28. By introducing two types of polyvalent salts into the materials of Examples 29 and 30, the performance of the secondary battery can be significantly improved compared to introducing one type of polyvalent salt in Example 7. This indicates that the action effect of the combined additive is superior to the improving action of a single salt.

Compared to Example 2, Examples 31-50 explored the addition of different amounts of polyvalent salt additives to the anode, cathode, and electrolyte, respectively. As a result, compared to Comparative Example 2, which did not contain additives, it was found that the secondary batteries of Examples 31 to 50 contained organic or inorganic salts of calcium, magnesium, aluminum, and beryllium, resulting in a significant improvement in cell performance. You can.

It should be noted that the present invention is not limited to the above embodiments. All embodiments that have the same technical idea and configuration and exhibit the same operation and effect within the scope of the technical solution of the present invention are included in the technical scope of the present invention. In addition, various modifications that can be conceived by a person skilled in the art may be made to the embodiment without departing from the spirit of the present invention, and other forms formed by combining some of the components in the embodiment are also included within the scope of the present invention.

1: Battery pack
2: Upper box
3: Lower box
4: Battery module
5: Secondary battery
51: case
52: electrode assembly
53: Top cover assembly

Claims (19)

As a secondary battery,
It includes a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or a secondary battery selected from germanium. According to paragraph 1,
The surface of the cathode material layer has an ADE ternary layer, where A is selected from alkali metal elements and is different from E, and D is silicon or carbon; The ADE ternary layer is a secondary battery formed by the interface passivator acting on the surface of the negative electrode material layer during at least one charging process of the secondary battery. According to claim 1 or 2,
the interface passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum. According to any one of claims 1 to 3,
The interface passivator is selected from at least one of substituted or unsubstituted C _1-20 carboxylates, and the substituent is C _1-6 alkyl, C _2-6 cycloalkyl, hydroxyl, amino, oxo group, acyl, C _1-6 alkylthio, phenyl, benzoylthio, phenylthio and phenoxy; iminoates; enoates; phosphate; sulfate; sulfonimide salt; sulfonate; benzoate; phthalate; acetylacetonate; inorganic oxoates; and a secondary battery of one or more types selected from double salts containing two or more types of cations of the above E. According to any one of claims 1 to 4,
A secondary battery in which the interface passivator is blended into at least one of the positive electrode material layer, the negative electrode material layer, and the electrolyte solution. According to any one of claims 1 to 5,
The ADE ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Li-C-Ca, Li-C-Mg, Li-C-Be, Li-C -Al, Na-Si-Ca, Na-Si-Mg, Na-Si-Be, Na-Si-Al, Na-C-Ca, Na-C-Mg, Na-C-Be, Na-C-Al selected from ternary hierarchies and combinations thereof;
Optionally, the ADE ternary layer is Li-Si-Ca, Li-Si-Mg, Li-Si-Be, Li-Si-Al, Na-Si-Ca, Na-Si-Mg, Na-Si-Be, A secondary battery selected from Na-Si-Al ternary layers and combinations thereof. According to any one of claims 2 to 6,
Before charging at least once, the positive electrode material layer includes 0.001% to 20% by weight, optionally 1% to 10% by weight of the interface passivator, based on the total weight of the positive electrode material layer. According to any one of claims 2 to 7,
Before charging at least once, the negative electrode material layer includes 0.001% to 20% by weight, optionally 0.05% to 5% by weight of the interfacial passivator, based on the total weight of the negative electrode material layer. According to any one of claims 2 to 8,
Before charging at least once, the electrolyte includes 0.001% to 20% by weight, optionally 0.1% to 5% by weight of the interfacial passivator, based on the total weight of the electrolyte. According to any one of claims 1 to 9,
A secondary battery wherein the negative electrode material layer includes a negative electrode active material, and the D50 of the negative electrode active material is 1 μm to 20 μm, optionally 1 μm to 10 μm. According to any one of claims 1 to 10,
The negative electrode material layer includes a negative electrode active material, and the Span value of the negative electrode active material is 0.9 to 1.8, optionally 0.9 to 1.2;
and
D90, D10, and D50 represent the corresponding particle sizes when the cumulative distribution percentage is 90%, 10%, and 50%, respectively. As a secondary battery,
The secondary battery is,
i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and
ii) A secondary battery manufactured through the step of performing at least one charge/discharge cycle on a secondary battery that has not gone through the above cycle. As a method of manufacturing a secondary battery,
i) A secondary battery that has not been cycled is manufactured by providing a negative electrode plate including a negative electrode material layer, a positive electrode plate including a positive electrode material layer, and an electrolyte solution; At least one of the cathode material layer, the anode material layer, and the electrolyte solution includes an interface passivator, and the interface passivator is a compound containing the element E, where E is lithium, sodium, beryllium, magnesium, potassium, calcium, aluminum, and gallium. or selected from germanium; and
ii) performing at least one charge/discharge cycle on the secondary battery that has not gone through the cycle to form an ADE ternary layer to obtain the secondary battery; A is selected from an alkali metal element and is different from E, and D is silicon or carbon. According to clause 13,
the interface passivator is selected from at least one of compounds of beryllium, magnesium, calcium, aluminum and gallium; Optionally, the interfacial passivator is selected from at least one of compounds of beryllium, magnesium, calcium and aluminum. According to claim 13 or 14,
The interface passivator is selected from at least one of substituted or unsubstituted C _1-20 carboxylates, and the substituent is C _1-6 alkyl, C _2-6 cycloalkyl, hydroxyl, amino, oxo group, acyl, C _1-6 alkylthio, phenyl, benzoylthio, phenylthio and phenoxy; iminoates; enoates; phosphate; sulfate; sulfonimide salt; sulfonate; benzoate; phthalate; acetylacetonate; inorganic oxoates; and a method of one or more types selected from polysalts containing two or more types of non-transition metal cations. According to any one of claims 13 to 15,
In step i), the interfacial passivator is blended into at least one of the anode material layer, the cathode material layer, and the electrolyte solution. A battery module comprising a secondary battery according to any one of claims 1 to 12 or a secondary battery obtained by the method according to any one of claims 13 to 16. A battery pack including the battery module according to claim 17. A secondary battery according to any one of claims 1 to 12 or a secondary battery obtained by the method according to any one of claims 13 to 16, a battery module according to claim 17, or a battery according to claim 18. An electrical device containing at least one of the packs.